Google Chrome V8 Type Confusion Vulnerability (CVE-2021-30551) Technical Advisory
Executive & SecOps Summary
SECOPS ASSESSMENTGoogle Chrome and Chromium-based browsers prior to version 91.0.4472.101
Remote attackers can trigger heap corruption and potentially execute arbitrary code via a crafted HTML page
Immediately update Google Chrome to the latest stable version (91.0.4472.101 or higher)
Affected Products & Version Scope
Remediation & Live Workaround Commands
PATCH & WORKAROUND1. Official Patch & Version Upgrade Commands
Update Google Chrome to the latest stable release using the system package manager or built-in update mechanisms.
# For Debian/Ubuntu-based systems
sudo apt-get update && sudo apt-get --only-upgrade install google-chrome-stable -y
# For RedHat/CentOS/Fedora-based systems
sudo dnf upgrade google-chrome-stable -y2. Temporary Workaround & Hardening Configuration
If immediate patching is not feasible, enforce strict sandboxing and restrict access to untrusted external websites via Group Policy or configuration files.
# Ensure Chrome is executed with sandbox enabled on Linux environments
google-chrome --enable-sandbox --disable-setuid-sandbox=false &3. Log Audit & IoC Verification Commands
Use the following script to audit the installed Google Chrome version across your Linux endpoints to identify vulnerable installations.
# Shell script to verify Google Chrome version
installed_ver=$(google-chrome --version | awk '{print $3}')
target_ver='91.0.4472.101'
if [ '$(printf '%s\
' '$target_ver' '$installed_ver' | sort -V | head -n1)' != '$target_ver' ]; then
echo '[ALERT] Vulnerable Chrome version detected: '$installed_ver'. Upgrade required.'
else
echo '[INFO] Chrome version '$installed_ver' is patched.'
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Technical Root Cause & Exploitation Mechanics
1. Vulnerability Overview & Root Cause
This vulnerability (CVE-2021-30551) is a Type Confusion (CWE-843) issue residing within the V8 JavaScript and WebAssembly engine of Google Chrome. The root cause lies in the JIT (Just-In-Time) compiler's optimization phase, where it incorrectly assumes the type of an object during runtime. This mismatch allows the engine to access memory using incorrect layout assumptions, leading to out-of-bounds memory access.
2. Exploitation Mechanics & Attack Scenario
An attacker exploits this vulnerability by hosting a malicious HTML page containing specially crafted JavaScript code. When a victim visits the page, the V8 engine attempts to optimize the malicious script. Due to the type confusion, the engine performs operations on memory locations with incorrect type definitions, enabling the attacker to corrupt the heap structure, bypass security boundaries, and execute arbitrary code within the browser renderer process.
3. Infrastructure & Business Impact
As a vulnerability listed in the CISA KEV (Known Exploited Vulnerabilities) catalog with an EPSS score of 0.647, this flaw represents an active threat. Successful exploitation can lead to complete compromise of the user's workstation. In an enterprise environment, this serves as an initial access vector for lateral movement, potentially leading to data exfiltration and ransomware deployment.
Official Vendor Advisories & References
Type confusion in V8 in Google Chrome prior to 91.0.4472.101 allowed a remote attacker to potentially exploit heap corruption via a crafted HTML page.
Frequently Asked SecOps Questions (CVE-2021-30551)
FAQQ1. How critical is CVE-2021-30551 and is it actively exploited in the wild?
CVE-2021-30551 is rated CVSS 8.8 (HIGH) with a 30-day EPSS exploitation probability of 64.7%. It is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, requiring immediate emergency remediation.
Q2. Which vendors and products are affected by CVE-2021-30551?
Primary impacted vendors include google across chrome. Scope summary: Google Chrome prior to version 91.0.4472.101 on Windows, macOS, and Linux
Q3. What temporary mitigations or workarounds exist for CVE-2021-30551 before patching?
[Mitigation] Immediately update Google Chrome to the latest stable version (91.0.4472.101 or higher) Follow the CLI remediation commands and interactive SecOps checklist on this page to restrict exposure prior to your maintenance window.
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